The crews were inside a utility vault Monday that runs under a U. campus parking lot near 300 S. 1850 East, according to Salt Lake City Fire Capt. Michael Harp. They were working on pipes that were supposed to be empty.
They "were actively working on open-ended pipes when they were actuated, resulting in the release of the high-temperature water and steam. The cause of the activation is under investigation by OSHA [Occupational Safety and Health Administration]," Harp said in a press statement.
The spot is near the U.'s HPER complex where existing pipe was to be tied into new lines serving the USTAR project to the north, according to Alan Rindlisbacher, a spokesman for the U.'s contractor, Layton Construction. It was unclear Monday afternoon if the accident involved the old or new infrastructure, officials said.
"We'll know more later, but right now our biggest concern is with those workers," Rindlisbacher said. No Layton employees were among the injured, all of whom were employed by subcontractors.
While the workers applied insulation, the water lines suddenly filled with super-heated water shortly before 11 a.m., spewing steam and boiling water into the vault, which is about 100 feet long.
Some 65 firefighters and six ambulances responded to the scene.
Paul and Susan Pace of Magna said their son, 25-year-old Ryan Dowland, was a foreman at the site. He suffered second-degree burns on his face, arms and legs as he tried to help the workers out of the tunnel but was not among the worst injured, the Paces said.
All the employees from the company he works for, Thermal West Industrial, are expected to recover, they said.
"We're very blessed," Susan Pace said. Paul Pace said his stepson called him after the accident, saying he was burned and needed help.
A message left with the president of Thermal West was not immediately returned. Officials from another subcontractor, KK Mechanical, declined comment.
The U.'s high-temperature water system, whose steel pipes have corroded over the years, has been prone to failure, resulting in 11 ruptures in 2009 and costing the U. about $2.5 million annually to keep the leaky system patched, officials testified before a legislative panel last February.
But Monday's mishap was not related to these infrastructure problems, according to Michael Perez, U. vice president for facilities.
"There was a malfunction in the system. It's really complicated. We're investigating to get confirmation on the exact cause," Perez said. It took a few hours to clear hot water from the vault, so it wasn't until late afternoon that officials could even begin to examine the water lines.
No buildings were evacuated. The university shut down the hot-water plant, located just west of the break, putting a stop to heat deliveries to much of campus.
"We have residual hot water in the lines to service the buildings for another several hours," Perez said. Monday's unseasonably balmy weather will forestall problems, but Perez expected to have the system back on line by Tuesday.
Hot water courses through 18 miles of steel pipe under the U. campus, much of it installed in the 1960s when the state's flagship underwent a spasm of growth. The insulated pipe was buried directly in the ground with a projected life of 20 to 30 years, Cory Higgins, director for plant operations at the school, told lawmakers last February.
Beginning in the 1990s, the network of pipes, which holds 400-degree water under intense pressure, has caused bigger and bigger headaches as failures mount. On an average day, 10,000 gallons of heated water leak from the aging pipes at a cost of $1,000, Higgins testified.
In 2009, parts of campus were without heat for a total of 105 days, and a plant operations mechanic was scalded earlier this year in a vault when a 35-year-old valve failed, causing second-degree burns on half the man's body, Higgins said.
The situation has become a crisis, jeopardizing the U.'s ability to conduct the research crucial to the state's economy, according to U. President Michael Young.
"The U. is hamstrung. We simply don't have the funds to continue these infrastructure projects. As they get more serious, they are more and more costly. We are paper-clipping and duct-taping it together at what will inevitably be an extraordinary cost to the state," Young said at the February hearing, pleading for $5 million to start replacing some of the most degraded sections of pipe.
The Legislature approved funding, and about a quarter of the pipe was to be swapped this year, including the section suspected in Monday's breach, according to Higgins.
Tribune reporter Bob Mims contributed to this story